Picture frame



FIG. 1 is a top, front, right perspective view of a picture frame showing my new design;

FIG. 2 is a front elevation thereof;

FIG. 3 is a rear elevation thereof; and,

FIG. 4 is a bottom plan view thereof, the top, left side and right side elevations being identical thereto. 

The ornamental design for picture frame, as shown and described. 